Fastener for pieces of jewelry

ABSTRACT

The present invention relates to a clasp for jewelry comprising a first hollow closure element which comprises a groove having an insertion aperture and extending at least partially around the circumference of the first closure element. The groove is configured to receive a fastening member of a second closure element which is insertable through the insertion aperture into the groove of the first closure element and whose cross-section is larger than the width of the groove. The first closure element comprises a wall at each of the two opposite end portions which ends the hollow first closure element, wherein the groove extends into the respective wall of the end portions and ends there.

The present invention relates to a closure device or a clasp for jewelry, in particular chains, such as for example necklaces.

Various embodiments of clasps for jewelry are known in the state of the art. DE 298 07 163 U1 discloses a jewelry chain provided with a conventional spring ring, wherein an annular intermediate member is provided for the connection of the spring ring to the end of the jewelry chain, said intermediate member having an original opening that can be closed by a weld seam, being configured flatly and being welded to the spring ring.

AT 379 301 C relates to a clasp for jewelry whose one part consists of a retaining ring, whereas its other part consists of plates connected to each other while leaving a space in between, wherein a pin is arranged in the space defined by the plates as an engagement member for the retaining ring.

Further clasps for jewelry are described, for instance in DE 82 23 357 U1, DE 18 61 755 A, DE 30 36 059 A1, DE 44 23 388 A1, DE 90 03 320 U1, DE 38 969, DE 23 32 531, DE 70 37 805 U1, EP 0 382 068 A1, EP 0 383 203, EP 0 498 300 A1, U.S. Pat. No. 2,644,992, U.S. Pat. No. 2,539,777 and WO 98/33411.

DE 201 16 646 U1 discloses a changing clasp for jewelry chains according to the bayonet principle comprising a receiving first part in the form of a tube comprising a base with a guide pin arranged perpendicularly to the longitudinal axis and a groove, as well as a second part to be introduced into the first part and being in the form of a tube comprising a shaft with a z-shaped guide groove and snap ring.

U.S. Pat. No. 3,224,060 discloses a clasp made of a tubular or generally cylindrical element having open ends. Two slots extending spirally or helically inward from the opposite ends are provided in the tubular element configured with open ends. The slots form an insertion opening at each of the ends. These insertion openings can be locked by means of two closure arms. The closure arms are pivotally mounted diametrically opposite to the insertion openings and can be locked by means of a locking head in the respective insertion opening.

U.S. Pat. No. 5,653,009 describes a clasp for connecting two ends of a piece of jewelry, said clasp comprising a cylindrical main body at whose one end an eyelet is securely attached for fastening a first end of the piece of jewelry. The cylindrical main body comprises a slot which extends in a straight or curved line and, at the end opposite the eyelet, passes into a front wall of the main body. A stud of a further eyelet can be inserted into this slot, a second end of the piece of jewelry being fastened to said further eyelet.

The present invention is based on the problem of providing an improved clasp for jewelry which permits reliable closing of jewelry, in particular chains, and at the same time is aesthetically appealing. A further problem underlying the present invention is the provision of a clasp for jewelry with which multi-row chains can be reliably closed and which is aesthetically appealing. These problems are solved by the clasps defined in the claims.

In one embodiment, the clasp for jewelry according to the invention comprises a first hollow closure element which comprises in its wall or its sheathing a slot or groove having an insertion aperture and extending at least partially around the circumference of the first closure element. The groove is configured to receive a fastening member of a second closure element which is insertable through the insertion aperture into the groove of the first closure element and whose cross-section is larger than the width of the groove. Thereby, the fastening member is secured in the hollow closure element after insertion into the insertion aperture and displacement along the groove. Furthermore, the first closure element comprises a wall at each of two opposite end portions which ends the hollow first closure element in the axial direction, i.e. in a direction between the ends of the piece of jewelry to be connected, wherein the groove extends into the respective wall of the end portions and ends there. The wall is preferably configured in an arched or conical manner and the groove preferably ends approximately in the center of the arch or cone.

The clasp according to the invention is in particular suitable for use in chains of any type. The hollow first closure element essentially forms a basic body into which the fastening member of the second closure element can be introduced. According to one embodiment, the first closure element is fastened to one end of the piece of jewelry, e.g. the chain, and the second closure element is fastened to an opposite end of the piece of jewelry. However, it is also possible to configure the first closure element as a separate member and to provide a second closure element at each of the two ends or of any two portions along the piece of jewelry, wherein, for closing the piece of jewelry, both second closure elements are introduced or inserted through the insertion aperture into the groove of the first closure element and displaced in the groove in opposite directions. The first closure element can be configured such that it receives several second closure elements at its two opposite end portions.

The first closure element is preferably configured essentially symmetrically to its longitudinal axis, i.e. the direction into which the clasp extends between the two ends of the piece of jewelry. The first closure element can be configured, for example, essentially hollow-cylindrically, spherically, multi-spherically, helically, multi-helically, cubically, multi-cubically and/or in a curved or angled tubular way.

The insertion aperture forming an enlargement of the groove is provided at a distance from the two end portions of the first closure element and preferably in a center region, in particular approximately in the middle of the axial extension of the clasp. The groove can be configured, for example, helically and performs preferably about ¼ to 5 windings, preferably about ½ to 3 windings, particularly preferably 1 to 2 windings along the length of the first closure element. The pitch of the helical groove or the windings generally depends on the diameter, the wall thickness and/or the length of the first closure element and preferably is between the range of 15° and 75°, more preferably between 30° and 60°.

According to an advantageous embodiment, a movable guided member, for example in the form of a pin, is provided inside the hollow first closure element. On account of its mass or rather mass inertia, this member serves as a safety element for the clasp according to the invention, since it counteracts a movement of the fastening member of the second closure element along the groove in the direction towards the insertion aperture.

As an alternative or a supplement thereto, it is advantageous to configure the first closure element in a bent (e.g. U-shaped) or angled (e.g. V-shaped) way for the purpose of improving the retention of the fastening member of the second closure element in the first closure element, wherein the insertion aperture is preferably provided on the inside of the bend or angle, in particular in the area of the vertex of the bend or angle. By means of this shape, the fastening member of the second closure element is purposefully kept apart from the insertion aperture.

As an alternative or a supplement thereto, the interior of the first closure element can be provided at one end portion or each of the two end portions with a labyrinth means through which the fastening member of the second closure element must be passed in order to secure the second closure element relative to the first closure element. This labyrinth means comprises, for example, a hollow sphere with an aperture, wherein the hollow sphere is arranged on an inner wall of the hollow first closure element in the region of the groove. The aperture faces away from the groove, wherein the groove extends both through the wall of the hollow first closure member and that of the hollow sphere.

Furthermore, it is possible to provide several first closure elements which are preferably essentially parallel to one another and coupled to one another in the transverse direction. A least one of the two outermost first closure elements, can comprise, for example, a helical groove starting at the insertion aperture and exhibiting a first screwing direction in the direction towards a first axial end portion and a helical groove exhibiting a second, reverse screwing direction in the direction towards a second opposite axial end portion. Preferably, both of the outermost first closure elements comprise a helical groove starting at the insertion aperture, extending in the direction towards a first axial end portion and exhibiting a first screwing direction and a helical groove starting at the insertion aperture, extending in the direction towards a second opposite axial end portion and exhibiting a second, reverse screwing direction.

It is preferred to provide at least one further hollow first closure element between the two outermost first closure elements which comprises a groove and an insertion aperture for receiving a fastening member of a second closure element. The groove of each further hollow first closure element is preferably essentially configured in its axial direction. The further hollow first closure element also comprises preferably a wall at both end portions terminating it in the axial direction, wherein the groove extends into the wall and ends there. Preferably, the further hollow closure element comprises such a wall at each of the two opposite end portions. The wall is preferably configured in an arched or conical manner and the groove preferably ends approximately in the center of the arch or cone.

The insertion aperture of the further hollow first closure element is provided at a distance from its two end portions and preferably in the center region, in particular approximately in the middle, of the axial extension of the closure element. The helical groove of the outermost first closure element(s) performs per screwing direction about ¼ to 1 winding, preferably about ½ winding, along the respective length of the first closure element.

According to a further embodiment, the invention relates to a clasp for jewelry comprising a first closure element, a second closure element configured essentially symmetrically thereto, and a locking element. Each of the first and the second closure elements comprises a cylinder portion for introducing one fastening member of the piece of jewelry each and for receiving a respective locking portion of the locking element, as well as a receiving portion provided parallel thereto for receiving the respective fastening member of the piece of jewelry.

Each of the first and second closure elements comprises a longitudinal groove or slot starting at a first end and leading into a groove or slot extending in the circumferential direction and finally into a further longitudinal groove or slot extending in the direction towards the first end. The further longitudinal groove, however, ends at a distance from the first end of the closure element. The locking element is preferably configured in an essentially H-shaped way, wherein the longitudinal portions or arms of the “H” can be introduced into the respective longitudinal grooves in the first and second closure elements, respectively.

Preferably, a projection is provided at each of the orifice regions of the longitudinal groove at the first ends of the two cylinder portions, and each of the two longitudinal portions of the H-shaped locking element is provided with a groove into which the respective projection is insertable. The lengths of the two longitudinal portions of the H-shaped locking element and of the projections are dimensioned such that the grooves of the locking element do not engage with the projections in the locked condition of the clasp, whereby the clasp is prevented from unintentionally opening.

Preferably, a groove is provided in each of the receiving portions of the first and second closure elements, the cross-section of said grooves being smaller than the width of the fastening members of the piece of jewelry. The locking element is preferably biased into a locked position by means of spring force.

Furthermore, the invention relates to a piece of jewelry, in particular a chain, comprising a fastening member which can be closed with the clasp according to the above description.

Preferred embodiments of the clasp according to the invention will be exemplarily described in the following by means of the drawings. The Figures show:

FIG. 1 a first embodiment of a clasp on a chain according to the invention;

FIG. 2 a a front view of a second embodiment of a clasp on a two-row chain according to the invention;

FIG. 2 b a rear view of the clasp according to FIG. 2 a;

FIG. 3 a a front view of a third embodiment of a clasp for a six-row chain according to the invention;

FIG. 3 b a rear view of the clasp according to FIG. 3 a;

FIG. 4 a a front view of a forth embodiment of a clasp for a five-row chain according to the invention;

FIG. 4 b a rear view of the clasp according to FIG. 4 a;

FIG. 4 c a schematic view of a locking element for the clasp according to FIGS. 4 a and 4 b;

FIG. 5 a a schematic view of a first embodiment of a fastening member for use with the clasp according to the invention;

FIG. 5 b a schematic view of a second embodiment of a fastening member for use with the clasp according to the invention;

FIG. 6 a modified embodiment of the clasp shown in FIGS. 4 a to 4 c;

FIG. 7 a a top view of a modified embodiment of the clasp shown in FIG. 1;

FIG. 7 b a front view of the clasp shown in FIG. 7 a;

FIGS. 8 a-d further modified embodiments of the clasp shown in FIG. 1;

FIG. 9 a a front view of a fifth embodiment of the clasp according to the invention;

FIGS. 9 b-h modified embodiments of the clasp shown in FIG. 9 a;

FIG. 10 a a front view of a sixth embodiment of the clasp according to the invention;

FIG. 10 b a modified embodiment of the clasp shown in FIG. 10 a;

FIG. 11 a a front view of a seventh embodiment of the clasp according to the invention;

FIG. 11 b a modified embodiment of the clasp shown in FIG. 11 a.

FIG. 1 shows a schematic view of a first embodiment of a clasp 2 for a piece of jewelry, e.g. a chain 4, according to the invention. The clasp 2 comprises a first essentially hollow-cylindrical closure element 6 having a helical slot or groove 8 comprising an insertion aperture 10. The groove 8 is configured to receive a fastening member 12 of a second closure element 14.

In the embodiment shown in FIG. 1, a second closure element 14 is provided at each end of the chain 4. The fastening member 12 of the second closure element 14 comprises a cross-section which is larger than the width of the groove 8. For this purpose, it is preferred to provide the second closure element 14 with a cross-sectional enlargement, for example in the form of a sphere, as the fastening member 12 on a bar or stick 16, wherein the sphere 12 serving as the fastening member can be introduced into the interior of the first hollow-cylindrical closure element 6 through the insertion aperture 10 and the stick 16 can be moved along the helical groove 8. To this end, the thickness or diameter of the stick 16 is to be dimensioned so as to be smaller than the width of the groove 8.

In the embodiment illustrated in FIG. 1, the first hollow-cylindrical closure element 6 further comprises a wall 18 at each of two opposite end portions which terminates or ends the hollow-cylindrical closure element 6 in the axial direction and forms a stop for the fastening member 12 of the second closure element 14. The groove 8 leads from a hollow-cylindrical region of the first closure element 6 into the wall 18 in the region of each end portion and ends there. For this purpose, the wall of the hollow-cylindrical region is advantageously configured so as to be curved away from the hollow-cylindrical region or conical, and the groove ends approximately in the center of the curvature or cone so that in the straight position shown in FIG. 1 the clasp 2 essentially keeps the chain 4 in the closed position after the two fastening members 12 have been displaced along the groove 8 up against the stop formed by each of the two opposite walls 18.

As shown in FIG. 1, the insertion aperture 10 is preferably provided in a center region, in particular approximately in the middle, of the axial extension of the clasp 2. The helical groove 8 exhibits preferably an essentially constant pitch and altogether one quarter to five windings, more preferably about one half to three windings, particularly preferably one to two windings along the length of the first closure element; from the insertion aperture 10 to each of the respective walls 18, the groove exhibits preferably about ⅛ to 2½ windings, in particular about ¼ to 1½ windings and particularly preferably ½ to 1 winding.

For opening the piece of jewelry 4, for example, one of the two second closing parts 14 can be moved with its stick 16 along the groove 8 up to the insertion aperture 10 and then the fastening member 12 can be taken out through the insertion aperture 10. The opposite second fastening member can remain coupled with the first hollow-cylindrical closure element 6 or likewise be taken out according to the above description.

In FIGS. 2 a and 2 b, a second embodiment of the clasp 2 according to the invention is illustrated. In this embodiment, several first hollow-cylindrical closure elements 6 are arranged essentially parallel to one another in the axial direction and coupled to one another in the transverse direction, preferably connected to one another along their entire length or along portions thereof so that several chains 4 can be closed by means of a single clasp 2. This is advantageous in particular for multi-row chains.

In the illustrated embodiment, two first hollow-cylindrical closure elements 6 are provided, wherein according to the front view illustrated in FIG. 2 a only end portions of the grooves 8 can be seen. As illustrated in the rear view in FIG. 2 b, each of the first hollow-cylindrical closure elements 6 comprises a separate insertion aperture 10 from which grooves 8 extend to the opposite ends of the first hollow-cylindrical closure elements 6. In each first hollow-cylindrical closure element 6, preferably a first helical groove 8 is configured which starts at the insertion aperture 10 and has a first screwing direction in the direction towards a first axial end and a second, reverse screwing direction in the direction towards a second opposite axial end. Furthermore, the screwing directions of the grooves 8 of the two first closure elements 6 in the respective portions from the insertion aperture to the first and second axial ends, respectively, are preferably also reverse to each other. This ensures that the clasp 2 reliably closes the chain 4 and keeps it in the closed position upon the insertion and displacement of the fastening members 12 against the respective axial ends. The two insertion apertures 10 possibly can also jointly form one single aperture.

In this embodiment, the second closure elements 14 are preferably designed in the same way as in the case of the above described first embodiment according to FIG. 1.

A third embodiment of a clasp 2 according to the invention is illustrated in FIGS. 3 a and 3 b. The basic structure of this embodiment essentially corresponds to that of the second embodiment, wherein additionally four further hollow-cylindrical closure elements 18 are provided between the two outermost first closure elements 6, each of which comprises a groove 20 and an insertion aperture 22 for receiving a fastening member 12 of a second closure element 14. The grooves 20 of the further hollow-cylindrical closure elements 18 preferably essentially extend in the axial direction. The insertion apertures 22 of the further hollow-cylindrical closure elements 20 are preferably provided at a distance from the axial ends and particularly preferably in a center portion, in particular approximately in the middle, of the axial extension of the clasp 2.

Each of the further hollow-cylindrical closure elements 18 also preferably comprises a wall at each of its end portions, said walls terminating or ending them in the axial direction, wherein the grooves 20 of respective hollow-cylindrical regions of the further closure elements 18 lead into the walls and end there. The walls formed at the end portions of the further hollow-cylindrical closure elements 18 are preferably configured so as to be curved outwards or conical and the grooves 20 end approximately in the center of the curvature or cone.

The helical grooves 8 of the outermost two first closure elements 6 preferably perform about ¼ to one winding, preferably about one half winding, per screwing direction from the insertion aperture 10 to the axial end along the length of the first closure element. In other words, each of the grooves 8 starts at the insertion aperture 10 and extends along approximately half the length of the first closure element 6 while performing approximately one quarter to one winding, in particular approximately one half winding around the circumference of the first closure element 6.

The clasp 2 according to the third embodiment is used analogously to the embodiments described in FIGS. 1 and 2 in that the fastening member 12 of the second closure element 14 of each of the chain parts of a multi-row chain is inserted into a corresponding insertion aperture 10 and the groove 8 or 20 connected thereto and is pushed or guided to the axial end. The chain is kept in the closed position in particular by the helical grooves 8 of the outermost two first closure elements 6 since they are configured so as to extend in reverse directions and thus the fastening elements cannot move away from the axial ends by themselves.

In the illustration according to FIGS. 3 a and 3 b, the clasp 2 is only connected to one end of the multi-row chain 4. The other end of the chain 4 can be similarly provided with second closure elements 14 and the closing operation can be performed according to the above description by insertion of the fastening members 12 into the respective insertion apertures 10, 22 and displacement of the second closure members 14 along the grooves 8, 20 towards the opposite axial ends.

The individual second closure elements 14 at one end of the chain can possibly be connected loosely or elastically to one another in such a way that the joint insertion into the insertion apertures and displacement towards the respective axial ends of the first closure elements 6, 18 is possible.

In all embodiments, the first and second closure elements either can be separate members or can also be connected detachably or non-detachably to the respective end of the piece of jewelry, e.g. the chain.

FIGS. 4 a, 4 b and 4 c show a fourth embodiment of a clasp 52 according to the invention. The clasp 52 according to this embodiment comprises two closure elements 54, 56 being essentially symmetrical to each other and a locking element 58. Each of the two closure elements 54, 56 has a cylinder portion 60 for inserting one or more fastening members 12 of one or more closure elements 14 of the piece of jewelry 4 and for receiving a respective locking portion 62 of the locking element 58. A receiving portion 64 is provided parallel to the cylinder portion 60 on each of the two closure elements 54, 56. Between each cylinder portion 60 and receiving portion 64, a connection aperture or groove is provided through which the fastening members 12 can be passed into the receiving portion after the insertion into the cylinder portion 60. For the purpose of reliably retaining the closure elements 14 of the piece of jewelry 4 in the receiving portion 64, the receiving portion 64 preferably comprises an undercut groove or is configured in a hollow-cylindrical form with a groove. A longitudinal groove 66 is preferably provided in each of the cylinder portions 60 of the two closure elements 54, 56, said longitudinal groove 66 starting at a first end and leading into a groove 68 extending in the circumferential direction and finally into a further longitudinal groove 70 in the direction towards the first end. Each of the first ends of the two cylinder portions is open and forms an axial aperture 76, while the opposite ends are preferably closed.

The locking element 58 is preferably configured so as to be essentially H-shaped, wherein the two arms or longitudinal portions of the “H” constitute the locking portions 62 which can be inserted into the two cylinder portions 60. The two longitudinal portions are connected to each other by a transverse portion 72. The locking element 58 is preferably biased in a locked position by means of a spring force which is applied by two pressure springs 74 provided in the cylinder portions 60.

For closing the chain 4 according to the fourth embodiment, first of all the fastening members 12 of the closure elements 14 are introduced one after the other into the axial aperture 76 at the first end of one of the cylinder portions 60, e.g. of the closure element 56, and pushed through the connection aperture (not shown) into the adjacent receiving portion 64 and lined up there in the axial direction. Subsequently, a longitudinal portion 62 of the locking element 58 is inserted into the axial aperture 76, wherein the transverse portion 72 is inserted into the groove 66 and moved forward along the groove against the spring force of the pressure spring 74 until the end of the groove 66 is reached and the groove 68 starts, which extends in the circumferential direction. At this point, the locking element 58 is rotated around the axis defined by the cylinder portion 60 so that the transverse portion 72 of the locking element 58 slides along the groove 68 extending in the circumferential extension until the transverse portion 72 has reached the end of the circumferential groove 68 and is pushed into the longitudinal groove 70 up to the end of it by the force of the pressure spring 74. In this position, the fastening members 12 of the closure elements 14 are locked in the receiving portion 64 of the chain. This position is shown in FIGS. 4 a and 4 b.

The opposite end of the chain 4 is inserted in the same way into the receiving portion 64 of the closure element 54 by means of its closure elements 14 with the fastening members 12 and locked there by means of the locking element 58.

For opening the piece of jewelry 4 it is not necessary that the fastening members 12 or closure elements 14 are pulled out of the receiving portions 64. It is rather sufficient to remove the locking element 58 by moving it into the opposite direction along the grooves 70, 68, 66 in order to separate the two closure elements 54, 56 from each other.

FIGS. 5 a and 5 b illustrate two embodiments of closure elements 14 provided at the end of the chain 4. According to FIG. 5 a, the spherical fastening member 12 is inserted into a hollow element by means of a stick or connection bar 16, wherein an eyelet 78 is provided at the end of the stick 16. The end of a chain can be affixed to this eyelet, for example. For example, the stick 16 can be flexibly passed through the hollow element 14 according to the illustration in FIG. 5 a so that the fastening member 12 is movable relative to the hollow element 14 along the stick 16. Alternatively, the stick 16 can be rigidly connected to the hollow element 14 of the closure element according to FIG. 5 b.

The embodiment of the clasp 52 shown in FIG. 6 is a modification of the embodiment shown in FIGS. 4 a, 4 b and 4 c. The clasp 52—similarly to the embodiment described in connection with FIGS. 4 a, 4 b and 4 c—comprises two closure elements 54, 56 being essentially symmetrical to each other (only one of which is shown in FIG. 6) and a locking element 58. A longitudinal groove 66 is provided in each of the cylinder portions 60 of the two closure elements 54, 56, said longitudinal groove 66 leading into a groove 68 extending in the circumferential direction and finally leading into a further longitudinal groove 70 in the direction towards the first end. Each of the first ends of the two cylinder portions is open and forms an axial aperture 76, while the opposite ends are preferably closed. In deviation from the embodiment shown in FIGS. 4 a, 4 b and 4 c, a projection 80 is provided on the first end of each of the cylinder portions 60 in the area of the axial aperture 76. Each of the two longitudinal or locking portions 62 of the H-shaped locking element 58 comprises a groove 82 into which the projection 80 can be introduced. The locking portion 62 can be introduced into the cylinder portion 60 by appropriately aligning the groove 82 relative to the projection 80, wherein the transverse portion 72 of the H-shaped locking element 58 can be passed through the grooves 66, 68 and 70. The length of the two longitudinal portions 62 of the H-shaped locking element 58 and of the two projections 80 is dimensioned such that the grooves 82 of the locking element 58 do not engage with the projections in the locked condition of the clasp 52, whereby the clasp 52 is prevented from unintentionally opening.

A modified embodiment of the clasp 2 according to FIG. 1 is illustrated in FIGS. 7 a and 7 b. This clasp—similarly to the embodiment according to FIG. 1—comprises a first essentially hollow-cylindrical closure element 6 having a helical groove 8 comprising an insertion aperture 10. The groove 8 in turn is configured to receive a fastening member 12 of a second closure element (not shown in FIG. 7). The clasp 2 according to the embodiment shown in FIGS. 7 a and 7 b differs from the clasp shown in FIG. 1 in particular in that the first closure element 6 is configured with respect to its longitudinal axis in a bent and/or angled manner, which is shown in the front view according to FIG. 7 b. This enables an improved retention of the fastening member 12 of the second closure element in the first closure element 6.

The insertion aperture 10 is preferably provided on the inside of the bend or angle, in particular in the area of the vertex of the bend or angle. By means of this shape, the fastening member 12 of the second closure element is purposefully kept apart from the insertion aperture 10.

It is illustrated in FIG. 7 b that in this embodiment a further jewelry element, e.g. a ring 78, can be advantageously attached to the first closure element 6 in the area of the bend or angle, wherein said ring can further cover and thus lock the aperture 10 when the piece of jewelry is worn.

Further modified embodiments of the clasp shown in FIG. 1 are schematically illustrated in FIGS. 8 a to 8 d. According to FIG. 8 a, the cross-section of the first closure element can also exhibit a generally oval form instead of a hollow-cylindrical form. In FIG. 8 b, the first closure element is essentially configured to be hollow-cylindrical, however with an axis swiveled by 90° as compared with the embodiment shown in FIG. 1 so that the two ends of the piece of jewelry can be attached to the lateral surface of the cylinder. In the modification shown in FIG. 8 c, the first and second closure elements are asymmetrically configured and exhibit a largely arbitrary shape. According to the embodiment shown in FIG. 8 d, the first closure element can be configured, for example, cubically. In the shown modification, two cubes are provided adjacently to each other in order to form the first closure element.

For the sake of clarity, the groove 8 is not shown in the embodiments according to FIGS. 8 a-d. Similarly to the previous embodiments, however, it can extend for example helically or along any other path at least partially around the circumference of the hollow first closure element 6. The same is true for the following embodiments described in connection with FIGS. 9 a to 9 h, 10 a to 10 b and 11 a to 11 b.

FIGS. 9 a to 9 h illustrate various modifications of a fifth embodiment of the clasp according to the invention. According to this embodiment, the first hollow closure element 6 is essentially spherically configured. It is preferred to arrange at least two spheres adjacently to each other in the longitudinal direction in order to form a double-spherical or multi-spherical first closure element 6. In FIG. 9 a, the double-spherical first closure element 6 receives a fastening member (not shown) of a second closure element at one or both end portions. For this purpose, the fastening element is inserted into the groove and passed to the opposite end portions as described in connection with FIG. 1.

The embodiments shown in FIGS. 9 b to 9 c are designed for multi-row jewelry. In these embodiments, the groove branches into two, three or more paths in the end portion(s) of the double- or multi-spherical first closure element 6 in order to receive one fastening member of each row of the multi-row piece of jewelry in each of these paths.

FIGS. 9 d to 9 h also illustrate clasps for multi-row jewelry, wherein in these embodiments not only one multi-spherical first closure element is provided in which the individual spheres are arranged adjacently to each other in the longitudinal direction but also in the transverse direction. The multi-spherical first closure elements can again be provided with branched grooves, as shown in FIG. 9 d, or the multi-spherical first closure elements have non-branched grooves. Preferably, the grooves extend only in the end spheres but not in the middle spheres.

For the purpose of better retaining the fastening members 12 in the spherical first closure elements, it is preferred, as shown in FIGS. 9 a to 9 e, to provide small spherical accommodations 84 on the walls in the end portions into which the fastening members of the second closure elements can be introduced in a labyrinth-like manner.

FIGS. 10 a and 10 b show a sixth embodiment of the clasp according to the invention. In this embodiment, the hollow first closure element itself is configured helically. The helix can, as shown in FIG. 10 a, extend over the entire length in one single direction or, as shown in FIG. 10 b, change its screwing direction for example in approximately the middle. In this embodiment, the groove (not shown) essentially extends along the entire length of the hollow first closure element parallel thereto.

In FIGS. 11 a and 11 b, a seventh embodiment of the clasp according to the invention is schematically shown. In this embodiment, two bent and/or angled tubular elements 86 are thinly connected to each other. The two tubular elements together form the hollow first closure element. Each tubular element is provided with a groove of its own (not shown) for receiving the fastening member of the second closure member. As shown in FIGS. 11 a and 11 b, the two tubular elements 86 can be designed in an essentially identical or symmetrical way and/or be arranged in a mirror-inverted way.

In all embodiments, the groove extends around at least part of the circumference of the first closure element. The groove can extend, for example, helically, it can, however, also extend partly in the longitudinal direction, partly in the circumferential direction.

For the purpose of securing the second closure element relative to the first closure element, it may be preferred to provide the inside of the hollow first closure element on one or both end portions with a labyrinth means through which the fastening member of the second closure element can be passed. This labyrinth means can be designed, for example, in the form of a hollow sphere having an aperture and being arranged on an inner wall of the hollow first closure element in the end portion in the region of the groove, wherein the aperture faces away from the groove and the groove extends both through the wall of the hollow first closure member and through that of the hollow sphere. In this design, the fastening member of the second closure element must be first introduced through the inlet aperture into the groove, then passed around the outside of the inner hollow sphere and then introduced through the aperture provided in the inner hollow sphere. The aperture is arranged such that, on account of the labyrinth means, it is highly unlikely that the fastening member simply slips out. Preferably, a holding nose is provided opposite the aperture in the inner hollow sphere on the inner wall of the hollow first closure element, wherein said holding nose contributes to making it difficult that the fastening member of the second closure element slips out.

Alternatively, it is also possible to lock the fastening member of the second closure element by means of a labyrinth plate provided in the hollow first closure element. This labyrinth plate is preferably arranged in the hollow of the first closure element such that it prevents the free passage of the fastening member in the groove. This can be realized, for example, in that the labyrinth plate blocks a considerable part of the hollow in the first closure element so that the fastening member must be passed around the labyrinth plate. Alternatively, the labyrinth plate can also almost completely block the hollow and only leave open a passage for a non-round cross-section of the fastening member.

The clasp according to the invention can be made of all materials typical for jewelry, such as metal, e.g. silver, gold, platinum and their alloys, and stainless steel, or plastics. 

1. A clasp for jewelry comprising a first hollow closure element which comprises a groove having an insertion aperture and extending at least partially around the circumference of the first closure element, wherein said groove is configured to receive a fastening member of a second closure element which is insertable through the insertion aperture into the groove of the first closure element and whose cross-section is larger than the width of the groove, wherein the first closure element comprises a wall at each of the two opposite end portions, said walls ending the hollow first closure element, and wherein the groove extends into the respective wall in the end portions and ends there.
 2. The clasp according to claim 1, wherein the first closure element is configured essentially symmetrically to its longitudinal axis.
 3. The clasp according to claim 1, wherein the first closure element is configured essentially as one of the group of configurations consisting of hollow-cylindrical, spherical, multi-spherical, helical, multi-helical, cubical, and multi-cubical and selectively formed to be one of the group of straight, curved or angled along a length thereof.
 4. The clasp according to claim 1, wherein the wall at each end portion is configured in an arched or conical manner and the groove ends approximately in the center of the arched or conical configuration.
 5. The clasp according to claim 14, wherein the insertion aperture is provided at a distance from the end portions and approximately in the middle of an axial extension of the closure element.
 6. The clasp according to claim 1, wherein the groove is helically configured and performs about ¼ to 5 windings, along the length of the first closure element.
 7. The clasp according to claim 1, wherein in an axial direction a plurality of first closure elements are arranged essentially parallel, and are selectively coupled to one another in a direction.
 8. The clasp according to claim 7, wherein one of an outermost two of the plurality of first closure elements comprises a helical groove starting at the insertion aperture and winding in a first direction of rotation towards a first axial end portion, and a second helical groove starting at the insertion aperture and winding in a reverse direction of rotation towards a second opposite axial end portion.
 9. The clasp according to claim 7, wherein at least one further hollow first closure element comprising a groove and an insertion aperture for receiving a fastening member of a second closure element is positioned between the two outermost first closure elements.
 10. The clasp according to claim 9, wherein the groove of the further hollow first closure element extends in the axial direction.
 11. The clasp according to claim 9, wherein the at least one further hollow first closure element comprises a wall at both end portions which ends the first closure element in the axial directions, wherein the groove extends into the respective wall and ends there.
 12. The clasp according to claim 11, wherein the walls are configured to be in the form of an arch or cone and the groove preferably ends substantially in the center of the arch or cone.
 13. The clasp according to claim 1, wherein the first closure element is configured such that it receives several second closure elements at both opposite end portions.
 14. The clasp according to claim 8, wherein the helical groove of at least one outermost first closure element wraps about ¼ to 1 winding along the respective length of the first closure element.
 15. The clasp according to claim 1, wherein at least one of the first and second closure elements is selectively connected by one of detachable or non-detachable connections to the piece of jewelry.
 16. The clasp according to claim 1, wherein a movable guided member is provided inside the hollow first closure element.
 17. The clasp according to claim 1, wherein the first closure element is selectively one of bent and angled configurations between the end walls.
 18. The clasp according to claim 17, wherein the insertion aperture is provided on an inner side of the selectively bent and angled configurations at a vertex of the bend and/or angle.
 19. The clasp according to claim 1, wherein the interior of the first closure element comprises at least at one end portion a labyrinth means through which the fastening member of the second closure element is inserrtable in order to secure the second closure element relative to the first closure element.
 20. The clasp according to claim 19, wherein the labyrinth means comprises a hollow sphere having an aperture, wherein said hollow sphere is arranged on an inner wall of the hollow first closure element in the region of the groove, wherein the aperture faces away from the groove and the groove extends both through the wall of the hollow first closure element and through a wall of the hollow sphere.
 21. A clasp for a piece of jewelry comprising two closure elements configured essentially symmetrically to each other, and a locking element, wherein each of the two closure elements comprises a cylinder portion for inserting at least one fastening member of the piece of jewelry and for receiving a locking portion of the locking element, as well as a receiving portion provided parallel thereto for receiving the at least one fastening member of the piece of jewelry.
 22. The clasp according to claim 21, wherein each of the cylinder portions of the two closure elements is provided with a longitudinal groove starting at a first end and leading into a groove extending in a circumferential direction and finally into a further longitudinal groove extending in the direction towards the first end.
 23. The clasp according to claim 22, wherein the locking element is configured in an essentially H-shaped way and longitudinal portions of the “H” are insertable into the respective grooves in the closure elements.
 24. The clasp according to claim 23, wherein a projection is provided at the first end of each of the two cylinder portions on an axial aperture of the longitudinal groove and each of the two longitudinal portions of the H-shaped locking element comprises a groove into which one projection is insertable, wherein the lengths of the two longitudinal portions of the H-shaped locking element and of the two projections are dimensioned such that the grooves of the locking element do not engage with the projections in the locked condition of the clasp, whereby the clasp, is prevented from unintentionally opening.
 25. The clasp according to claim 21, wherein each of the receiving portions of the two closure elements comprises a groove whose cross-section is smaller than widths of the fastening members of the piece of jewelry.
 26. The clasp according to claim 21, wherein the locking element in at least one of the cylinder portions is biased into a locked position by means of spring force.
 27. A piece of jewelry having at least one fastening member in combination with a clasp according to claim
 1. 28. (canceled) 